Tapping-mode atomic force microscopy and phase-imaging in higher eigenmodes

Tapping-mode atomic force microscopy (TM-AFM) is a powerful tool to study soft biological samples. Higher eigenmodes of the vibrating cantilever offer enhanced signal and smaller time constants increasing the sensitivity of the tapping probe as compared to conventional TM-AFM. The first five eigenmodes of a υ-shaped silicon cantilever were investigated with respect to their suitability for imaging. Stable imaging was possible in the first and third modes. Phase imaging in the third mode was extremely sensitive to surface inhomogeneities and surface contamination particles not visible in standard TM-AFM.